Gravity Falls X Female Reader

Stan has a Brother?!

Recap
I hit these numbers/letters: A1BC3 the door opened......
(Y/N) P.O.V
I looked around me Wendy is looking at a magazine, and Soos is outside. I walked in, closed the door, walked down the stairs, and took an elevator to the 3rd floor of the basement.
It was a secret lair like that bunker in the woods. Then, I saw the first two journals on a countertop. OMG it's the first two journals! I have to tell Dipper. I grabbed the journals when I heard a beep. I looked up and saw a timer counting down. I looked straight and saw a weird portal looking thing. I ran to the elevator, ran up the stairs and snuck out of the "basement". After I closed the door, I noticed that
nobody was here. I went to the attic hoping to find Dipper and Mabel there, but I was wrong.
A few minutes later, a grappling hook broke the window and the Pines twins came zooming in on the grappling hook. "What a grand entrance you two." I said as I highfived them. " T-thanks (Y/N)," Dipper stuttered. I laughed softly as I sat on my bed.
"Where were you guys? " I said. "We were taken by the government guys. Where were you?" Mabel said with curiosity."I... it's.. never mind." I said as I started pacing back and forth in the room. "I need to show you guys something. Quick, follow me." I said as I walked to the gift shop and hit the same numbers/letters on the vending machine.
When we got down to the lab, I pulled out the journals from my (f/c) hoodie. "This is where I was earlier. I also found these." I said as I handed Dipper the other two journals. "What?!" Dipper yelled at me.
"I'm sorry I was scared." I said as Dipper pulled out his journal and turned to a certain page in each book and set them up. It looked like Bill Cipher. He pulled out his black light. pointed it at the journals, and read what it said.
Mabel pointed to the timer and said, "It's the final countdown, just like they always sung about!!" If we weren't scared right now, we would've busted out laughing. I walked to the other end of the lair and saw a door to the right of me. I opened it and saw three switches. "Guys, you might want to come check this out." I said as the Pines twins came out, lined up by a switch, and I said, "Turn these!! Together!!" After we turned them, we turned around and a cover of the shut down switch came off.
Dipper ran to the button and said, "This all stops... Now!" He lowered his hand and Stan came running in and said, "Don't touch that button!!"
-30 seconds later brought you by Bill-
"Grunkle Stan,"Mabel said," I trust you." She let go of the lever and Dipper and I said," Are you crazy we're all going to.." We blacked out. When I sat up, there was a man coming out of the portal. He grabbed the 1st journal and put it in his coat. "What... Who is that?" Dipper asked. "The author of the journals, " Stan said as the guy took off his goggles and scarf, " my brother."
"Is this the part where somebody faints? " Mabel said. "I am so on it." I said as the ground met me very fast.
When I woke up, I opened my eyes and saw Mabel, Dipper, Stan, and Stan looking at me. Wait what?! Why are there two Stans?!